Family: Apocynaceae

Asclepias tuberosa, known as butterfly milkweed, butterfly weed, or pleurisy root, is a striking perennial native to North America. Its clusters of bright orange to yellow-orange flowers are highly attractive to butterflies, bees, and other pollinators. Unlike many other milkweeds, it does not produce milky sap when cut. This hardy, drought-tolerant species prefers sunny locations and well-drained soils, making it a popular choice in pollinator gardens and native plant landscapes.

Although Asclepias tuberosa is not known to be naturalized in Hawai‘i, it has been rated high risk due to a number of traits that could create problems if it were to establish in the wild. These include its ability to thrive in disturbed areas, potential to spread by seed, and traits shared with other milkweeds that have become invasive elsewhere. Because of these concerns, it is not recommended for planting in the Islands. For pollinator-friendly gardens, native Hawaiian species are a more pono choice.

High Risk Traits:

• Broad climate suitability (>5 hardiness zones, but primarily temperate)
  
• Possibly naturalized (unverified)
  
• Regarded as weedy in some circumstances
  
• Other Asclepias species are invasive
  
• Unpalatable to browsing and grazing animals
  
• Toxic to mammals and people
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively by underground shoots
  
• Low levels of self-compatibility
  
• Reaches maturity in 2-3 years
  
• Seeds dispersed by wind and intentionally by people

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Provides food for monarch butterfly larvae
  
• Generally occurs in high light environments (might not be able to invade areas with dense shade)
  
• Low reproductive output reported from native range